A driver circuit for controlling one or more external power switches (e.g. power transistors, such as Field Effect Transistors, FETs), typically comprises a voltage regulator in order to generate a low level logic voltage (e.g. at 3V) from a higher level supply voltage Vcc (e.g. at 12-15V). The logic voltage is typically used as a power supply for one or more logic components (e.g. a microcontroller) of the driver circuit. Furthermore, the driver circuit typically comprises one or more drive units for generating the gate control signals for the one or more external power switches, respectively. A gate control signal (which is applied to the gate of a corresponding power switch) may alternate between a high voltage (e.g. at the supply voltage Vcc) and a low voltage (e.g. at ground) at a commutation cycle rate and with a duty cycle (specifying the amount of time of high voltage within a commutation cycle), thereby operating the corresponding switch in an on/off mode (alternating between on-state and off-state).
During standby, when no gate control signals are generated by the driver circuit, the voltage regulator typically only provides a relatively low current, i.e. the driver circuit incurs only low losses (with little heat dissipation). On the other hand, during operation of the driver circuit, when one or more gate control signals are generated, the current through the voltage regulator may be significant (e.g. in the range of 10 mA). This results in a power loss and heat generation within the voltage regulator. The heat should to be dissipated e.g. using an additional heat sink on the driver circuit. However, the additional heat sink impacts the size and the cost of the driver circuit (in particular the package costs).
The present document addresses the above mentioned technical problems. In particular, the present document describes a driver circuit (and a corresponding method) which is configured to remove the need for an additional heat sink due to power losses incurred by a voltage regulator comprised within the driver circuit.